Fluid sterilization apparatus

ABSTRACT

A fluid sterilization apparatus including a sterilization chamber having a cavity therein, and a nozzle for receiving pressurized fluid and directing a spray of the fluid into the cavity. An electron beam generator having an exit window is mounted to the sterilization chamber for directing a beam of electrons through the exit window and into the cavity of the sterilization chamber to irradiate the spray of fluid. The nozzle is configured to direct the spray of fluid substantially parallel and proximate to the exit window.

RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/251,210, filed on Dec. 4, 2000. The entire teachingsof the above application are incorporated herein by reference.

BACKGROUND

[0002] Some waste treatment plants employ electron beam technology forirradiating sewage for sterilization purposes. In a typical application,the sewage is caused to flow over a waterfall and the falling curtain ofsewage is irradiated by an electron beam emitted by an electron beamgenerator. In order to ensure thorough sterilization, extremely largeelectron beam generators must be employed to penetrate through thefalling curtain, typically in the range of 1 to 10 million eV. Otherlarge systems have been employed for irradiating fluids such as waterflowing through a piping system. In such systems, the fluid isirradiated while flowing through the piping system.

SUMMARY

[0003] The present invention is directed to a fluid sterilizationapparatus which does not require a large electron beam generator. Thefluid sterilization apparatus includes a sterilization chamber having acavity therein. A nozzle is included for receiving pressurized fluid anddirecting a spray of the fluid into the cavity. An electron beamgenerator having an exit window is mounted to the sterilization chamberfor directing a beam of electrons through the exit window and into thecavity of the sterilization chamber to irradiate the spray of fluid. Thenozzle is configured to direct the spray of fluid substantially paralleland proximate to the exit window.

[0004] In preferred embodiments, the fluid is pumped by a pump andparticles in the fluid are filtered from the fluid by a filter. Thenozzle directs a thin, flat film of fluid into the sterilizationchamber. In one embodiment, the film of fluid is 0.004 to 0.005 inchesthick. The cavity of the sterilization chamber includes an outletthrough which the sterilized fluid is removed. In one embodiment, thecavity of the sterilization chamber includes a recycling passage fordirecting a portion of the spray of fluid back for further irradiation.In this embodiment, a wall between the cavity outlet and the recyclingpassage directs any fluid from the spray of fluid unable to pass overthe wall into the recycling passage.

[0005] The present invention is also directed to a fluid sterilizationapparatus including a container for containing a supply of fluid. Awheel system having circumferential surfaces is rotatably mounted withinthe container. The wheel system is configured for extending a portion ofthe wheel system above the supply of fluid with rotation of the wheelsystem drawing a film of fluid upwardly out of the supply of fluid onthe circumferential surfaces. A doctoring member is positioned forcontrolling the thickness of the film of fluid on the circumferentialsurfaces of the wheel system. An electron beam generator is positionedfor irradiating the film of fluid with a beam of electrons to sterilizethe fluid. A fluid removal member is positioned for removing sterilizedfluid from the wheel system.

[0006] In preferred embodiments, the wheel system includes a first wheelrotatably mounted within the container for drawing the film of fluidfrom the supply of fluid. In one embodiment, the wheel system furtherincludes a second wheel rotatably contacting the first wheel forreceiving fluid from the first wheel to be irradiated by the electronbeam generator.

[0007] The present invention fluid sterilization apparatus can have asterilization region and an electron beam generator that are bothcompact in size. Consequently, the present invention can be maderelatively inexpensively in comparison to the large systems in the priorart. When in a compact size, the present invention apparatus is smallenough to be easily installed within both new or existing systems ordevices requiring fluid sterilization, and in addition, can also be aportable unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

[0009]FIG. 1 is a side view of an embodiment of the present inventionfluid sterilization apparatus.

[0010]FIG. 2 is an enlarged view of the lower portion of the electronbeam generator and the sterilization chamber assembly from the sideopposite to that depicted in FIG. 1.

[0011]FIG. 3 is a sectional view of a portion of another embodiment ofthe sterilization chamber.

[0012]FIG. 4 is a side schematic view of another embodiment of thepresent invention fluid sterilization apparatus.

[0013]FIG. 5 is a side schematic view of still another embodiment of thepresent invention fluid sterilization apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Referring to FIGS. 1 and 2, fluid sterilization apparatus 10 isan embodiment of the present invention that is employed for sterilizingfluid. Such fluids 42 can include water, cooling fluid for machinery,etc. Fluid sterilization apparatus 10 includes a pump 16 for pumpingfluid 64 to be sterilized from a fluid reservoir 54 (FIG. 1), a filter14 for filtering particles from the fluid 64, a reaction orsterilization chamber 24 into which the fluid 64 is sprayed forsterilization, and an electron beam generator 12 that is mounted tosterilization chamber 24 for irradiating the fluid 64 with an electronbeam 38 (FIG. 2). The electron beam generator 12 includes an exit window36 through which an electron beam 38 is directed, and the sterilizationchamber 24 includes a nozzle 28 which is aimed into a cavity or passage34 within sterilization chamber 24. Fluids 64 to be sterilized areintroduced as a spray 42 of fluid 64 by nozzle 28 which is directed intocavity 34 proximate to the exit window 36 of the electron beam generator12 (FIG. 2). The electron beam 38 from the electron beam generator 12irradiates the spray 42 of fluid 64 with elections e⁻ within cavity 34thereby sterilizing the fluid 64 by killing organisms, viruses andbacteria in the fluid 64. The sterilized fluid 64 can then be recoveredfor reuse or disposal from fluid outlet 32.

[0015] A more detailed description of fluid sterilization apparatus 10now follows. Pump 16 has a fluid inlet 18 for pumping the fluid 64 thatis to be sterilized from fluid reservoir 54 (FIG. 1). Pump 16 providespressurized fluid 64 to filter 14 which is coupled to the pump 16 by afluid conduit 20. The filtered fluid 64 is provided to sterilizationchamber 24 through a fluid conduit 22 coupled between filter 14 andsterilization chamber 24.

[0016] The filtered fluid 64 enters sterilization chamber 24 underpressure through passage 26, as shown by arrow A (FIG. 2). The passage26 is in fluid communication with nozzle 28 which is upstream fromcavity 34. Typically, the nozzle 28 is configured to produce a spray 42of fluid 64 into cavity 34 that is a relatively flat, thin, andhorizontal film of fluid 64. The spray 42 of fluid 64 enters cavity 34via entrance 40 and may widen in thickness slightly while passingthrough cavity 34, as shown. The nozzle 28 in one embodiment consists ofa single nozzle such as a horizontal slot for producing a thin flat filmof fluid that is about 0.004 to 0.020 inches thick. The nozzle assemblycan also be an opening about 0.004 to 0.020 inches in diameter forforming a spray of fluid 42 about 0.004 to 0.020 inches thick.Alternatively, nozzle 28 can have a series of horizontally arrangednozzles.

[0017] Cavity 34 has a first portion 34 a adjacent to nozzle 28 which isgenerally shallow and formed in the upper portion of sterilizationchamber 24 that is closest to the exit window 36 of electron beamgenerator 12. In FIGS. 1 and 2, the first portion 34 a is shown to beelongated. The first portion 34 a of cavity 34 has an upper area forminga reaction or sterilization region 30 through which the spray 42 offluid is directed and a lower wall 33 which slopes downwardly into fluidoutlet 32 located at a second portion or downstream end 34 b of thecavity 34. The upper portion of cavity 34 is relatively horizontal orparallel to the exit window 36 of election beam generator 12 to allowthe spray 42 of fluid 64 to pass through horizontally or parallel toexit window 36. The spray 42 of fluid 64 typically is within 1 inch ofexit window 36 with about ¼ inch being more preferable. The slope oflower wall 33 of cavity 34 allows any fluid 64 thereon to flowdownwardly toward fluid outlet 32. Typically, sterilization chamber 24is formed of stainless steel, but alternatively, can be formed of othersuitable materials.

[0018] A mounting/sealing arrangement 51 between the electron beamgenerator 12 and the sterilization chamber 24 mounts and seals electronbeam generator 12 and the sterilization chamber 24 together in a mannerwhere exit window 36 is sealed above cavity 34 in close proximitythereof (FIG. 2). The exit window 36 of electron beam generator 12 ispositioned over sterilization region 30. An irradiation window oropening 52 into cavity 34 faces the exit window 36 of electron beamgenerator 12 to allow entry of the electron beam 38 into cavity 34.Cavity 34 is enclosed and sealed from the exterior environment so thatexternal contaminants other than fluid 64 cannot enter, whereby cavity34 can remain relatively sterile during operation. The electron beamgenerator 12 is typically of a design that is hermetically sealed andmay be similar to those described in U.S. Pat. No. 5,962,995, U.S.patent application Ser. No. 09/349,592, filed Jul. 9, 1999, and U.S.patent application Ser. No. 09/209,024, filed Dec. 10, 1998, thecontents of which are incorporated herein by reference in theirentirety. Usually, electron beam generator 12 operates in the range of125 kv to 300 kv. Alternatively, other suitable electron beam generatorscan be employed as well as voltages below 125 kv and above 300 kv.

[0019] When the spray 42 of fluid 64 is directed into the cavity 34 ofsterilization chamber 24 (FIG. 2), the electrons e⁻ of the electron beam38 penetrate the spray 42 of fluid 64 and damage or destroy structuresof any organisms, bacteria or viruses within the fluid. This disables orkills the organisms, bacteria or viruses, thereby sterilizing the fluid.In some cases, chemical contaminants in the fluid can also be destroyed.The nozzle 28 is configured and positioned relative to cavity 34 andelectron generator 12 to direct the spray 42 of fluid 64 substantiallyparallel and proximate to the exit window 36 of electron beam generator12 as well as perpendicular to electron beam 38, for maximum irradiationby electron beam 38. This positions the spray 42 as close as possible tothe exit window 36 to be irradiated by the electron beam 38 where theintensity is greatest and the exposure time is the longest. Since cavity34 is typically occupied by air, the intensity of the electron beam 38decreases with increasing distance from the exit window 36. In addition,having a thin, flat, film spray 42 of fluid 64 allows maximumpenetration through the fluid 64 by the electron beam 38 for thoroughsterilization. Making the spray 42 of fluid 64 into a thin flat film0.004 to 0.020 inches thick allows the electron beams 38 of electronbeam generators 12 operating at 125 kv to 300 kv to sufficientlypenetrate the spray for sterilization. Typically, the spray 42 of fluid64 is made about 0.004 inches thick for penetration by an electron beam38 emitted by an electron beam generator 12 operating at about 125 kv,about 0.005 inches thick at about 150 kv, and about 0.020 inches thickat about 300 kv. A thickness of 0.004 inches to 0.005 inches is the mostcommon for use with electron beam generators 12 operating at 125 kv to150 kv, respectively. In one embodiment, a low density gas such ashelium can be pumped into cavity 34 to increase the range of electronbeam 38. Alternatively, cavity 34 can be subjected to a vacuum toincrease range.

[0020] The sterilized fluid is directed downwardly by the curved rearwall of cavity 34 and then flows downwardly from sterilization chamber24 through the fluid outlet 32 for recovery or otherwise, as shown byarrow B. This can be back to the fluid reservoir 54 or other desiredlocations. Pump 16 may be employed to either continuously recirculatefluid for continuous sterilization or may be operated periodically forintermittent sterilization. If only periodic operation is required,fluid sterilization apparatus 10 can be a portable unit which is coupledto the fluid supply for sterilizing the fluid only when needed. In someapplications, only weekly sterilization may be required.

[0021] In one embodiment, the electron beam generator 12 is about 11inches in diameter. The combined height of electron beam generator 12and sterilization chamber 24 for an electron beam generator of such sizeis about 18.5 inches. Such a small size of a fluid sterilizationapparatus 10 allows easy installation within both new and existingsystems or devices for sterilizing fluids. The small size also allowsfluid sterilization apparatus 10 to be portable. Additionally, fluidsterilization apparatus 10 can be sized to sterilize fluid associatedwith more than one system or device. In such a case, there may be acentral reservoir for the fluid. The fluid inlet 18 and outlet 32 offluid sterilization apparatus would be arranged in fluid communicationwith the central reservoir. Also, the size of electron beam generator 12and sterilization chamber 24 may be increased or decreased for greateror lesser capacity, for example, thicker or thinner sprays 42 of fluid64. It is apparent that any supply of suitable fluid can be sterilizedwith fluid sterilization apparatus 10. Typical applications may includebut are not limited to sterilizing drinking water or other fluids.

[0022] Referring to FIG. 3, sterilization chamber 50 is anotherpreferred sterilization chamber assembly which differs fromsterilization chamber 24 in that sterilization chamber 50 includes acavity 35 having a wall 44 between fluid outlet 32 and a downwardlyangled recycling passage 46. Wall 44 forms a collection region 48 whichcollects or traps any spray 42 a of fluid 64 that does not pass overwall 44, usually when nozzle 28 first begins to spray the fluid 64. Thefluid 64 collected in collection region 48 typically does not becomesufficiently irradiated to an acceptable level of sterilization.Insufficient irradiation can include irradiation by only a portion ofelectron beam 38 or by passing through electron beam 38 too far awayfrom exit window 36 where the intensity of the electron beam 38 at thatdistance is decreased. The collected fluid 64 travels down recyclingpassage 46 in the direction of arrow C for further irradiation.Recycling passage 46 can either bring the fluid 64 back to the fluidreservoir 54 or to a pump which pumps the fluid 64 back into the systemjust prior to passage 26. The spray 42 of fluid 64 that passes over wall44 is parallel and proximate to exit window 36, and therefore, becomessufficiently sterilized by electron beam 38. The sterilized fluid thenexits sterilization chamber assembly 50 via fluid outlet 32. Thesterilization chamber 50 can be configured so that the sterilizationregion 30 that is irradiated by electron beam 38 extends downstream orbeyond wall 44. The sterilization chamber 50 is designed to besterilized by operating electron beam generator 12 instead of washingwith chemicals. Although wall 44 is shown to have a surface angledtoward nozzle 28, alternatively, wall 44 can be straight, curved or havea surface extending away from nozzle 28.

[0023] Referring to FIG. 4, fluid sterilization apparatus 55 is anotherembodiment of the present invention. Fluid sterilization apparatus 55includes an irradiation assembly 60 that is provided with fluid 64 to betreated from a fluid reservoir 54. The fluid 64 is pumped by pump 56through conduit 58 and nozzle 58 a into container 62 of irradiationassembly 60. The container 62 is able to contain a supply 64 a of thefluid 64. The irradiation assembly 60 includes a wheel system having awheel 66 that is rotatably mounted within the container 62 about a pivotpoint 68 for rotation in the direction of arrow R. Wheel 66 can bedriven by any suitable conventional means. A portion of the wheel 66extends above the supply 64 a of fluid 64. Rotation of the wheel 66draws an initial film of fluid 72 upwardly out of the supply 64 a offluid 64 on the circumferential surfaces 66 a of wheel 66. A doctoringmember or blade 70, typically having a straight edge, is positionedrelative to the circumferential surfaces 67 of wheel 66 to control orreduce the thickness of the film 72 to form a thinner film of fluid 74suitable for irradiation. The doctoring member 70 pushes the excessfluid 64 back down toward the supply 64 a of fluid 64. Typically, a filmof about 0.004 to 0.020 inches in thickness is preferred. The film offluid 74 travels on wheel 66 in the direction of arrow D and isirradiated with electrons e⁻ of an electron beam 38 from electron beamgenerator 12 in a sterilization region 76 to sterilize the film of fluid74. The film of fluid 74 is sufficiently thin for the electron beam 38to penetrate in order to kill or destroy organisms, viruses andbacteria. Electron beam generator 12 is similar to that employed influid sterilization apparatus 10 and typically operates in the range of125 kv to 300 kv. After irradiation, the sterilized film of fluid 80 isscraped from wheel 66 by a fluid removal member 78 which contacts thecircumferential surfaces 67 of wheel 66 and is angled downwardly toallow the sterilized fluid 80 to be recovered by flowing to a desiredlocation or back to reservoir 54. Typically, the fluid removal member 78includes a straight edge for contacting wheel 66 and scraping thesterilized fluid 80 therefrom. Sterilization apparatus 55 is designed tocause the fluid 64 to move past electron beam generator 12 and flow onlywhen wheel 66 is rotating since wheel 66 must draw the fluid 64 upwardlyout of supply 64 a. If wheel 66 does not rotate, the fluid stays incontainer 62. Consequently, when sterilization apparatus 55 is not beingoperated, the fluid 64 will not leak of flow from container 62.Typically the film of fluid 74 is about 0.004 inches thick forpenetration and sterilization by an electron beam 38 emitted by anelectron beam generator 12 operating at about 125 kv, about 0.005 inchesthick at about 150 kv, and about 0.020 inches thick at about 300 kv. Athickness of 0.004 inches to 0.005 inches is the most common.Alternatively, films of fluid thinner than 0.004 inches and thicker than0.020 inches can be formed with electron beam generator 12 beingappropriately sized for sufficient sterilization. The wheel 66 can bemade to have a diameter in the range of about 6 inches to 12 inches sothat fluid sterilization apparatus 55 is small enough to be portable.Alternatively, wheel 66 can have smaller or larger diameters.

[0024] Referring to FIG. 5, fluid sterilization apparatus 85 is anotherembodiment of the present invention which differs from fluidsterilization apparatus 55 in that irradiation assembly 84 includes awheel system having a second wheel 66 a rotating about pivot point 68 aand rotatably contacting the first wheel 66 above the supply 64 a offluid 64. Typically, wheel 66 a is driven by wheel 66, butalternatively, can be independently driven. Wheel 66 a rotates in thedirection of arrow R₁ and transfers the film of fluid 74 from wheel 66to wheel 66 a, becoming a film of fluid 82. The film of fluid 82 movesin the direction of arrow D₁, and is irradiated by electron beam 38 fromelectron beam generator 12. The sterilized film of fluid 80 is thenremoved from wheel 66 a by fluid removal member 78. If wheel 66 a isindependently driven, wheel 66 a can be spaced slightly away from wheel66 and rotated in either direction.

[0025] While this invention has been particularly shown and describedwith references to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the scope of the inventionencompassed by the appended claims.

[0026] For example, although the spray 42 of fluid 64 of fluidsterilization apparatus 10 is shown to be horizontal, alternatively, thespray 42 of fluid 64 and the electron beam generator 12 may bepositioned at an angle different from that shown in the figures (such as90° or 180° and angles in between). Consequently, the terms employedabove to describe the present invention such as upper, bottom,horizontal, etc. are used to describe the relative position ofcomponents shown and are not meant to limit the orientation of thepresent invention. In addition, the spray of fluid 42 can have adifferent configuration such as circular rather than flat. Furthermore,the filter 14 may be positioned upstream of the pump 16. The fluidsupplied to the nozzle assembly 28 can be pressurized by means otherthan pump 16, such as by pressurized gas, by delivering the fluid fromthe bottom of a reservoir, etc. Also, the fluid sterilizationapparatuses described above may be employed for treating fluids fornon-sterilization purposes such as curing or initiating chemicalreactions, and may treat non-water based fluids. Finally, variouscomponents of the different embodiments of the present invention can becombined together or omitted and be sized to suit the application athand.

What is claimed is:
 1. A fluid sterilization apparatus comprising: a sterilization chamber having a cavity therein; and a nozzle for receiving pressurized fluid and directing a spray of the fluid into the cavity; and an electron beam generator having an exit window, the electron beam generator being mounted to the sterilization chamber for directing a beam of electrons through the exit window into the cavity to the sterilization chamber to irradiate the spray of fluid, the nozzle being configured to direct the spray of fluid substantially parallel and proximate to the exit window.
 2. The apparatus of claim 1 further comprising a pump for pumping the fluid.
 3. The apparatus of claim 2 further comprising a filter for filtering particles from the fluid.
 4. The apparatus of claim 1 in which the nozzle directs a thin, flat film of fluid within the sterilization chamber.
 5. The apparatus of claim 4 in which the film of fluid is about 0.004 to 0.005 inches thick.
 6. The apparatus of claim 4 in which the cavity of the sterilization chamber includes an outlet through which fluid that is sterilized is removed.
 7. The apparatus of claim 6 in which the cavity of the sterilization chamber includes a recycling passage for directing a portion of the spray of fluid back for further irradiation.
 8. The apparatus of claim 7 in which the cavity includes a wall between the cavity outlet and the recycling passage for directing any fluid from the spray of fluid unable to pass over the wall into the recycling passage.
 9. A fluid sterilization apparatus comprising: a sterilization chamber having a cavity therein; a nozzle for receiving pressurized fluid and for directing a spray of the fluid into the cavity, the spray of the fluid being a thin, flat, film of fluid; and an electron beam generator mounted to the sterilization chamber for directing a beam of electrons into the cavity of the sterilization chamber to irradiate the spray of fluid.
 10. The apparatus of claim 9 in which the film of fluid is about 0.004 to 0.005 inches thick.
 11. A fluid sterilization apparatus comprising: a container for containing a supply of fluid; a wheel system having circumferential surfaces, the wheel system being rotatably mounted within the container, a portion of the wheel system for extending above the supply of fluid with rotation of the wheel system drawing a film of fluid upwardly out of the supply of fluid on the circumferential surfaces; a doctoring member for controlling the thickness of the film of fluid on the circumferential surfaces of the wheel system; an electron beam generator for irradiating the film of fluid with a beam of electrons to sterilize the fluid; and a fluid removal member for removing sterilized fluid from the wheel system.
 12. The apparatus of claim 11 in which the wheel system comprises a first wheel rotably mounted within the container for drawing the film of fluid from the supply of fluid.
 13. The apparatus of claim 12 in which the wheel system further comprises a second wheel rotatably contacting the first wheel for receiving fluid from the first wheel to be irradiated by the electron beam generator.
 14. A method of forming a fluid sterilization apparatus comprising: providing a sterilization chamber having a cavity therein; forming a nozzle for receiving pressurized fluid and directing a spray of the fluid into the cavity; and mounting an electron beam generator to the sterilization chamber, the electron beam generator having an exit window and for directing a beam of electrons through the exit window into the cavity of the sterilization chamber to irradiate the spray of fluid, the nozzle being configured to direct the spray of fluid substantially parallel and proximate to the exit window.
 15. The method of claim 14 further comprising providing a pump for pumping the fluid.
 16. The method of claim 15 further comprising providing a filter for filtering particles from the fluid.
 17. The method of claim 14 further comprising forming the nozzle to be capable of producing a thin, flat film of fluid.
 18. The method of claim 17 further comprising forming the nozzle to be capable of producing the film of fluid 0.004 to 0.005 inches thick.
 19. The method of claim 17 further comprising forming the cavity of the sterilization chamber with an outlet through which fluid that is sterilized is removed.
 20. The method of claim 19 further comprising forming a recycling passage in the cavity of the sterilization chamber for directing a portion of the spray of fluid back for further irradiation.
 21. The method of claim 20 further comprising forming a wall within the cavity between the cavity outlet and the recycling passage for directing any fluid from the spray of fluid unable to pass over the wall into the recycling passage.
 22. A method of sterilizing fluid comprising: directing a spray of pressurized fluid from a nozzle assembly into a cavity of a sterilization chamber; and irradiating the spray of fluid with a beam of electrons from an electron beam generator mounted to the sterilization chamber, the electron beam generator having an exit window through which the beam of electrons is directed, the nozzle being configured to direct the spray of fluid substantially parallel and proximate to the exit window.
 23. The method of claim 22 further comprising pumping the fluid to the nozzle assembly with a pump.
 24. The method of claim 23 further comprising filtering particles from the fluid with a filter.
 25. The method of claim 22 further comprising forming the spray of fluid as a thin, flat film of fluid.
 26. The method of claim 25 further comprising forming the film of fluid about 0.004 to 0.005 inches thick.
 27. The method of claim 25 further comprising removing fluid that is sterilized from the cavity of the sterilization chamber through an outlet.
 28. The method of claim 27 further comprising recycling a portion of the spray of fluid back for further irradiation through a recycling passage.
 29. The method of claim 28 further comprising recycling an initial spray of fluid.
 30. The method of claim 31 further comprising directing any fluid into the recycling passage that is unable to pass over a wall within the cavity between the cavity outlet and the recycling passage.
 31. A method of forming a fluid sterilization apparatus comprising: providing a container capable of containing a supply of fluid; rotatably mounting a wheel system having circumferential surfaces within the container, a portion of the wheel system for extending above the supply of fluid with rotation of the wheel system drawing a film of fluid upwardly out of the supply of fluid on the circumferential surfaces; providing a doctoring member for controlling the thickness of the film of fluid on the circumferential surfaces of the wheel system; providing an electron beam generator for irradiating the film of fluid with a beam of electrons to sterilize the fluid; and providing a fluid removal member for removing sterilized fluid from the wheel system.
 32. The method of claim 31 further comprising providing the wheel system with a first wheel rotatably mounted within the container for drawing the film of fluid from the supply of fluid.
 33. The method of claim 32 further comprising providing the wheel system with a second wheel rotatably contacting the first wheel for receiving fluid from the first wheel to be irradiated by the electron beam generator.
 34. A method of sterilizing fluid comprising: drawing a film of fluid upwardly out of a supply of fluid contained within a container on circumferential surfaces of a rotating wheel system rotatably mounted within the container, a portion of the wheel system extending above the supply of fluid; controlling the thickness of the film of fluid on the circumferential surfaces of the wheel system with a doctoring member; irradiating the film of fluid with a beam of electrons from an electron beam generator to sterilize the fluid; and removing the sterilized fluid from the wheel system with a fluid removal member.
 35. The method of claim 34 further comprising drawing the film of fluid from the supply of fluid with a first wheel of the wheel system.
 36. The method of claim 35 further comprising rotatably contacting a second wheel of the wheel system with the first wheel for receiving fluid from the first wheel for irradiation by the electron beam generator. 